The present invention relates to a structure for mounting in a compressor a filter for eliminating foreign substances contained in the oil separated from refrigerant gas under a discharge pressure in the compressor.
Japanese Unexamined Patent Application Publication No. 55-29040 discloses a compressor having a filter for eliminating foreign substances contained in the oil separated from refrigerant gas under a discharge pressure. The compressor of this Publication has a cylinder head having a discharge chamber therein, an oil collection chamber and an oil reservoir. An oil separator is located between the discharge chamber and the oil collection chamber. The oil reservoir is located below the oil collection chamber and communicates therewith via a communication hole. The oil reservoir also communicates with a crank chamber of the compressor via an oil return passage having a first hole, a second hole and a third hole. A capillary is inserted in the first hole and serves as a throttle member. The capillary is provided at one end thereof adjacent to the oil reservoir with a cylindrical wire mesh filter.
In this compressor, oil contained in the refrigerant gas discharged from the discharge chamber is separated from the refrigerant gas by the oil separator. The separated oil is collected in the oil collection chamber and then flows through the communication hole to be reserved in the oil reservoir. The oil reserved in the oil reservoir flows into the oil return passage through the capillary. Because foreign substances contained in the oil then passing through the capillary are eliminated by the wire mesh filter, the capillary and the oil return passage will not be clogged with the foreign substances.
Japanese Unexamined Patent Application Publication No. 2002-276544 discloses a structure for mounting a control valve with a filter in a variable displacement compressor and a device for assembling the filter in the control valve. The filter of this Publication includes a frame member having at the joint thereof a hook and a hook holder. The hook is removable from the hook holder. The compressor has therein a mounting hole for receiving therein the control valve and the inner wall of the mounting hole is formed so as to complement the outer shape of the control valve. This inner wall has an inclined surface at the position where the filter is fitted. This inclined surface tapers toward the inner part of the mounting hole. As the control valve is being inserted into the mounting hole, the frame member of the filter is pressed radially inward by the tapered surface. Thus, the hook of the frame member of the filter is engaged with the hook holder and the frame member is snugly fitted in the tapered hole, so that the filter is received in the hole at a predetermined position for covering the high-pressure port of the control valve.
However, the former Publication No. 55-29040 does not provide a detailed description about the structure for connecting the capillary and the wire mesh filter. Judging from the drawings of this Publication, it can be thought that the capillary is merely covered with the wire mesh filter after being inserted into the first hole. Therefore, there is a fear that the wire mesh filter may be removed from the capillary due to vibration of the compressor.
According to the latter Publication No. 2002-276544, there is no fear that the filter provided in the mounting hole may be removed from the control valve. However, this filter is held to the control valve by using the tapered surface of the inner wall of the mounting hole. Therefore, high dimensional accuracy is required for the filter and the inner wall of the mounting hole.
The present invention, which has been made in light of the above problems, is directed to a structure for mounting a filter in a compressor, which prevents the filter from being removed from a mounting member for the uncomplicated structure in mounting the filter to the mounting member. In addition, the present invention is directed to a structure for mounting a filter in a compressor, which alleviates the requirement of high dimensional relative accuracy between the filter and the inner wall of the receiving hole for receiving therein an object to be mounted.